Infections in a pediatric patient cohort with acute lymphoblastic leukemia during the entire course of treatment

To assess the type, frequency, severity, and outcome of all infectious episodes in a pediatric patient cohort with acute lymphoblastic leukemia (ALL) from a single institution during the entire length of leukemia treatment.

Eighty-six patients were treated according to a modified ALL Berlin–Frankfurt–Munster protocol. Retrospective analysis of all types of infections according to the treatment phase and the degree of neutropenia is presented.

A total of 610 infectious episodes were recorded. Most infections were documented during maintenance (57%), followed by the induction phase (20.3%). During maintenance, 347 episodes were encountered, with nonspecific viral upper respiratory tract infections (URIs) being the commonest diagnosis (40.0%). Additionally, 38 of 58 total specific viral infections occurred during maintenance: 16 herpes simplex, 7 varicella, 10 herpes zoster infections [varicella–zoster virus (VZV), 45%]. The majority of bacteremia and fever of unknown origin occurred during induction (20%). The number of Gram-negative bacteremia was 50% of the total (26 of 52). The majority of the infections (59.5%) occurred without neutropenia [absolute neutrophil count (ANC) >1,000 μl⁻¹]. Fewer infections (9.3%) were recorded with concurrent very severe neutropenia (ANC <100 μl⁻¹), although 38.5% of positive blood cultures were documented with severe neutropenia. No infection-related fatality occurred.

Most of the severe infections occurred during induction. Gram-positive bacteremia and Gram-negative bacteremia were almost equal. URIs were the commonest infections during the entire treatment and during maintenance. Specific viral infections represented a smaller percentage of the total (VZV was the commonest pathogen). Infectious complications represented a significant morbidity factor, but notably, mortality was negligible.